nanog mailing list archives
Re: different flavours of uRPF [RE: register.com down sev0?]
From: "Chris L. Morrow" <christopher.morrow () verizonbusiness com>
Date: Fri, 27 Oct 2006 16:45:59 +0000 (GMT)
On Fri, 27 Oct 2006, Tony Li wrote:
Pekka Savola wrote:On Thu, 26 Oct 2006, Tony Li wrote:It was possible to implement BCP38 before the router vendors came up with uRPF.Further, uRPF is frequently a very inefficient means of implementing BCP 38. Consider that you're going to either compare the source address against a table of 200,000 routes or against a handful of prefixes that you've statically configured in an ACL.Isn't that only a problem if you want to run a loose mode uRPF? Given that loose mode uRPF isn't very useful in most places where you'd like to do ingress filtering, this doesn't seem like a big issue..Strict mode uRPF is likely to be implemented by performing a full forwarding table lookup and then comparing the packet's incoming interface to the interface from the forwarding table result.
Pekka might have meant wouldn't you build a seperate 'urpf table' per interface perhaps? (just guessing at his intent) though there is only one 'urpf table' which is the fib, right?
Current thread:
- Re: register.com down sev0?, (continued)
- Re: register.com down sev0? Gadi Evron (Oct 26)
- 10,352 active botnets (was Re: register.com down sev0? Valdis . Kletnieks (Oct 26)
- Re: 10,352 active botnets (was Re: register.com down sev0? Matthew Crocker (Oct 26)
- Re: 10,352 active botnets (was Re: register.com down sev0? Jack Bates (Oct 26)
- Re: register.com down sev0? Fergie (Oct 25)
- Re: register.com down sev0? Jared Mauch (Oct 26)
- Re: register.com down sev0? Daniel Senie (Oct 26)
- RE: register.com down sev0? Tony Li (Oct 26)
- different flavours of uRPF [RE: register.com down sev0?] Pekka Savola (Oct 26)
- Re: different flavours of uRPF [RE: register.com down sev0?] Tony Li (Oct 27)
- Re: different flavours of uRPF [RE: register.com down sev0?] Chris L. Morrow (Oct 27)
- Re: register.com down sev0? Jared Mauch (Oct 26)
- RE: register.com down sev0? Gadi Evron (Oct 27)
- Re: register.com down sev0? Gadi Evron (Oct 26)
- Re: register.com down sev0? Patrick W. Gilmore (Oct 26)
- Re: register.com down sev0? Randy Bush (Oct 26)
- Re: register.com down sev0? Michael . Dillon (Oct 27)
- Re: register.com down sev0? Daniel Senie (Oct 26)